Improvement in roasting-furnaces for ores



2 Sheets-Sheet l. J. COLLOM. ROASTING FURNAGE FOR ORES.

No. 106,553. Patented Aug. 23, 1870.

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2 Sheets-Sheet 2. J. COLLOM. ROASTING FURNAGE POR ORES.

No. 106,553. Patented Aug` 23, 1870.

UNITED STATES PATENT' OFFICE.

JOHN coLLoM, .Or EMPIREOI'IY,y COLORADO TERRITORY.

IMPROVEMENT IN RQASTlNG-FURNACES FOR ORES.

Speciticationforming part of Letters Patent No. 106,553, dated August 23, I87; antedated August 15, 1870.

To all whom it may coiwewt.:

Be it known that I,'JOHN OOLLOM. of Empire City, in the county ot' Clear Creek, Golorado Territory, have invented a new and lisef ul Improvement in Met allurgie Furnaces; and I do hereby declare that the following is a full,

clear, and exact description thereof, which will enable others skilled in the art to make and use lthe same, reference being had to the aecompanying drawings, forming part of this specilication.

The nature of my invention relates to improvements 'iu furnaces', whereby the perfect desulphuri'zing, oxidizing, chloridizing, and

smelting of metallic ores and metallurgical products are effected in larger quantities and at less cost for manual labor, fuel, tools, and repairs of furnace than has hitherto been the case.

-In the accompanying drawings,-Figure1 represents a side elevation of a furnace provided with my improvements. Fig. 2 represents a longitudinal sectional elevation of the same. Fig. 3 represents a transverse sectional elevation. Fig. 4.: represents a horizontal section. Figs. 5 to 9 represent details.

Similar letters of reference indicate correspondin g parts.l

The general arrangements of the furnace consistot' three'-;desulphurizing, oxidizing, and

chloridizing chambers, A, B., and O, an inclined reaction-bed, D, a smelting-bed, E, fireplace F, mixing and feeding apparatus G, stirring-machine H, condensing-chamber I, and a steam-generating apparatus, J. I

The'chambers are formed by thesides and ends of the furnace and the four arches a., a, a, and a, which have each an open space at one end, but on alternate sides of the furnace. These maybe built of common brick when it is not intended to lmelt refractory ores in the fusingbed. On each side the chambers are provided .with holes b1; to introduce air, steam, chlorine and other gases, and to examine the charge. The reaction-bed 'D is built of lirebrick or other suitable material, and on its side has doors c c c to allow working the charge. The melting-bed is also builtfof tire-brick, and its peculiar construction and its relation to the lire-place F has for, its object the production of. the' greatest heat immediately behind the bridge d.

The mixing and feeding apparatus G consists cfa W-shaped box, e, divided by the partitions ff in to several compartments, each provided with an aperture, g, and a valve, h, to be raised and lowered by the handles it', which latter are supported by the cheek-bolts jj, secured to thebeam K, a'scraper, l, worked by means of the rod m, and the valves n n. The arrange.-

Inent is such that the scraper will rake certain regulated quantities ot each lkind of ore contained in the separate compartments.

The stirring-machine H consists ot' the pipes O 0 O, which may be ordinary gaspipe, orV

round, square, 01 oblong iron tubes. In Wide furnaces more than one tube to carry and cool the'raks in eachchamber would be required.'

The rakesp p may be of cast or wrought iron, and provided with the fiukesqq, made of clay or other fire and sulphur proof material, and attached to the rake-beams by the rods r r, slightly bent at their lower end to iirmiy hold the clay. The ends of the linkes are pointed to prevent the ore from accumulating under them, and their section above the taperis represented in-Fig. Figs. 'and 6show the side andl longitudinal section, and Figs. 8 and 9V endl and transverse section, ot' the tiukes.

The angle s is made more acute than s', for

the purpose' otl causing the ore to pass.slowly in the directionot's". The obtuse angle s' being set toward the [ire-place F in the chambers A Vand C and ,towardthe chimney in chamber B, -the ore will pass through the furnace, as desired. The rakes are of two lengths, and the flakes of. the longer ones set so as to pass between and till up the grooves made by those of the shorter. The ends of the longer rakes enter the metallic guides tt, by which they are 'kept in their proper position, and the tubes O o o. are supported by the rollers u u.

For the purpose of cooling the tubes and rakes a stream of water (or air when watercaunot be had) enters the pipes O at v and escapes at w, froin whence, when necessary, it is conveyed into a tank. (Not shown.) The water will be conveyed to the pipes at t1, and from. them at zo, by flexible hose; and the guides t t, which are hollow, arc'cooled b'y water entering at a'. t

The stirring-machine has a reciprocating motion, which may be imparted vto it by any suitable application of power at z and a, and the length of vits stroke is equal to twice the distance-from center to center of the takes, so that the set of grooves made by the one in the ore. may be iilled by the other, and thusbe constantly exposing a new surface ofthe orc to the influence ofthe heat-and gases. The ends a' a! a! of the roasting-chambers A, l, and O are temporarily closed by brick after the stirringmachine has been set in its place, and can be opened by the removal of the brick when the rakes need to be withdrawn for repairs. The pipes are put-together by suitable connections, so that they may be separated at the angles b b to bc withdrawn when necessary.

From the chamber A the gases pass down the liuc c into the condensing chamber I', divided by the partition-(1', where, owing to their diminished velocity and temperature, they dci posit much of the iinc ore and volatilized metals-dead, silver, and goldwhich they bear. From the condensing-chalnber the gases escape into the air through the chimney It', and the deposited dust is drawn out through the holes .il il ,l il.

The steam-generating apparatus J, placed in the` condensing-chamber and heated by the gases, is for thc purpose oi' generating steam to be introduced into the roasting-chainbers to facilitate theremoval ofthe sulphur andthe oxidation and chlorination of the ores and to regulate the temperature. Steam having a pressure ofth'ree or four pounds per square inch is very suitable for this purpose, and the boiler holding steam of this density may lie-supplied with water already hot from the tankj and through the pipe lc', thus avoiding the expense and labor ot' providing a leed-pump and economi/.luga part of the heat held by the water used iu cooling the stirring-machine.

The amount of heat to he absorbed by the water aird steam may beregulatedby partially covering the upper part of the boiler with sand supported by an iron frame, and the pressure of the steam in the boiler may be regulated by the safety-valve q.

This furnace is designed especially to treat eresl of lead, copper, silver, and gold, butmay be used for other purposes. The great length ot' the three roasting-chambers, together with that; of the reaction and meltin g bedsand their relative position, constitutes an important feature. 1t enables the maintenance of a high temperature in thc melting and reacting beds and a moderate heatI in the upper chambers, and consequently the subjection ofthe ore to a gradually-increasing temperature from the time it enters the furnace uutil it iswithdrawn l ough, as the ore on lthe top of the ridges falls to the bottom of the grooves, and is next pressed outward, and iin-ally rises to the surface again, thus causing all the orc to pass repeatedly from the surface to the bottom of the layers. The arrangement oi' one chamber above another tends to economize heat, as that which passes through the root' of one chamber: is taken up by thc oreabove it; and milch of the valuable metals volatilized in the meltingbed will be condensed in passing over the cold ore in the upper chamber. The melting-bed, on account ofthe high heat prevailing there, will require to be repaired occasionally, which may be done without disturbing the rest of the furnace.

The following are some of the ways in which this furnace may be used intrcating different kinds of orcs.

Galena should be roasted in the chambers, so as on re'aclnng'the head of thereaction-bed most ofthe lead should be converted into oxide and sulphate, then the increased temperature would cause thc oxide and vsulphate to react uponeach other and upon the undecoinposed sulphide, producing sulphurous acid, metallic lead, and a slag containing oxide ot' lead. The latter should he reduced to metallic lead by throwing into the furnace and mixing with the ore a suitable quantity of charcoal.

' In carryingout this mode ot'smelting it is essen'- tial that the oxidation in the chambers 4should 4be carried soV far that yaf ter the reactions have taken place oxide, and not sulphide, oflead shouldy remain in the slag, as the former can readily be reduced by charcoal, while the latter would require to be reroa-sted, or to be reduced by metallic iron. All ores while on the reaction an d smelting beds would need to be stirred had been changed into sulphate and oxide ot' lead;v then on the reaction-bed the high temperature there prevailing would cause the silica present to react upon the sulphate and oxide, resulting in the dislodgment of sulphuric acid and, the formation of silicate of lead,

together with the silicates ot' linie, barytmand iron, when such bases occur in the ore.

The silicate of lead may be treated in the melting-bed with charcoal and metallic iron,

giving as a product metallic lead and silicate? of iron and an impoverished slag, all of which may then bc drawn oif into a suitable receptacle. Or, when circumstances are favorable, the partially-fused silicates may be drawn from the furnace, allowed tov cool, broken into fragments, and smelted, with iron or iron ore, in a. cupolafurnace- As it is important that as much as possible ofthe sulphuric acid should be expelled before the mass becomes fused, it is intended by a judicious regulation of the tire, and admis' sion of air and steam through the holes at the head o f the inclined hearth, to cause the commencement of 'the reactions at the upper end of the bed, that they may be continued until the mass reaches the melting-hed and there becomes fused.

The various kinds of ores, matts, &c., of which the charge had to be compounded, on being put-into the compartments of the mixing and feeding apparatus, could, by a proper attention to the valves h h, be intimately mixed in the exact proportions desired, and fed into the furnace with a regularityY and precision unattainablevby manual labor; and therateat which the ores pass through the furnace can be nicely governed by a proper regulation of the speed ot' therstirring-machine, and by the depth ot' the ore in the furnace.

Copper py'rles and other sulphureted copper ores should be roasted in the chambers and reach the head of the reaction-bed as soon as only suicient sulphur remained to draw all the copperinto a matt, and enough iro oxidized to forni a fusible slag with the silica present, and then, on being exposed tothe heat of the reaction-bed, the silica would combinewith the ,oxide of iron, and the copper with the sulphur,

andon reaching the higher .heat of the lmelting-bed the perfectly-fusedA matters would separate into a substratum of sulphides or matt, and a superstratum of silicates or slag. The latter would be drawn out at the-door l and cast away as useless, 'and the matt ruu out through the hole m into a tank of water, to be granulated, and afterward-returned to the furnace, to undergo a similar roasting and smelting to remove the remaining' sulphur, iron, and other impurities. In Workingores of this class, the introduction of steam through t-he holes b I) would facilitate the removal of sulphur and oxidation of metals.

Silver ores may be treated in this furnace by being mixed with the silicious lead ores, and roasted and smelted, as has already been described, theslver lconcentrated in the lead and afterward separated by cupellation; by heilig mixed with copper and iron pyritesthe silver `concentrated in a matt and separated therefrom -by a process of i liquation, amalgamation, or precipitation; or by a chlorination roasting preparatory tor amalgamation. In roasting for amalgamation the silver ore, pyrites,and salt would be put into the compartments of the mixing and feeding machine, and mixed and fed into the furnace in the usual way, roasted under a moderate heat in the chambers A aud- B, and then under the higher temperature of chamber C, to cause a 'reaction of the sul phuric acid of the metallic sulphates u pon the 'sodium of the salt, resulting in an evolution of the "chlorine, which would. immediately combine' with the silver, forminga chloride of silver readily decomposed by iron and taken up by mercury in the process of amalgamation.

`In treating silver'ores .containing only a. small quantity of base-metal sulphides--such as zinc, copper, lead, antimony, 82e.- the chlorination of the silver and the decomposition `of the'sulphates would be thoroughly accomplished on reaching the head of the reaction-bed, and Wouldnot need to pass through the reaction bed, butwould be discharged through the aperture. n by the removal ofthe brick stopper 0;. but when the ore abounds in base-metal sulphides the latter part of the. roasting should be effected under the higher heat of the reaction-bed, in order to th co npose the sulphates and chlorides of zinc, cop` per, lead, Snc., as these remaining `iu the ore would seriously interfere with the amalgamation. -The decomposition of the base-metalsulphates and chlorides .will be greatly facilitated and the use of saltc'conomized by allowing a suitable quantity of steam to pass into the furnace from the boiler J through the pine-S r r- Gold ores, whether sul phurous or quartzose, can'be successively treated in this furnace by being mixed, roasted, and snielted with. siliciouslead ores or with sul ph ureted copper ores, as already mentioned.

Auriferous ir'ou p \rite s could be partially roasted inl the chambers and their melted-in the fusion-bed, by which the gold would be concentrated in an iron matt, from which it could be'readily separated by being melted with lead ores, or by an amalgamation, or a precipitation process; or the sulphurous ores could be well roasted in the chambers and then in the reaction-bed to decompose the sulphates of iron and copper, and then be Withdrawn from the furnace to be treated by the amalgamation or chlorination process.

' Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination ofthe inclined reaction' bed D and melting-hearth with a mechanical roastingfurnace, all arranged as and' for the purpose specified.`

2. The combination of scraper, scraper-rod, and regulating-valves, each constructed and operated as described.

3. The improyed-stirring-rakes p p, having tapering fiukes q q thereon to prevent an ac' cumulation of the roasting ore beneath them, and having angles s s', of diEere/nt acuteness, so that when reciprocated they will stir the ore at each half-stroke and cause it to pass slowly -i'n the direction of the larger angle.

4. As an improvement in metallic furnacerakes, the construction of the ukes q, in the manner shown and described.

Witnesses: JOHN GtOLLOM.

J. H. YENLEY, WILLIAM LIGHT. 

